June 03, 2010

Alcanivorax borkumensis - oil-eating bacteria, where are you?

I've celebrated the extraordinary things that microbes can do (or at least
the little we actually know about what they can do) in other posts,
but now, surely, is the time to seek their help on a grand scale in the Gulf of
Mexico. Now that the initial segments of sand berms have been approved
by the Federal Government ("based on a thorough expert analysis"..... see my
previous three posts), it seems that we can only wait and reap the fruits of
this exercise. These projects seem to have been the sole focus of political
rhetoric over the last weeks, and the possibilities for actually getting rid of
the oil have been relegated to the sidelines of what, in my view has become a
political game - to the detriment of the health of the Gulf. In this context, I
have to ask why more emphasis is not being placed on the use of Alcanivorax
borkumensis, a natural bacterium that has a voracious appetite for
hydrocarbons.

Given that there are hundreds
of natural oil seeps in the northern Gulf, spewing out an estimated 70,000
tonnes (roughly equivalent to 20 million US gallons) of oil every year, why do
we not see a more oil-polluted Gulf in normal circumstances? One big reason is
the natural activity of bacteria like Alcanivorax borkumensis. No, I'm
not supporting Rush Limbaugh and his demented and twisted interpretation
of facts, but one fact is that natural processes can help in the
kind of catastrophe we are facing. But those natural processes don't have the
critical mass to deal with events on this scale - they need help. The use of
oil-eating microbes has been the subject of research around the world for many
years, and it is, of course, complex - different bacteria have a liking for
different hydrocarbons and graze the ocean buffet with discrimination; their
activity levels vary with conditions of ocean chemistry and temperature. BUT:
they work. Microbiologists at the University of Bangor, in Wales, have just
released the results of their work on these critters in the interests of
possibly immediate application to the Gulf oil slick. Christopher Gertler, one
of the team, is quoted as saying "The potential for 'bioremediation' as
this technique is called is huge. It is, I believe, the only technique that
would effectively remove oil that is distributed over such large distances as
are being seen in the current Gulf of Mexico oil spill."

In the interests of raising awareness, to whatever extent this blog can,
here's the complete press release:

A natural tool to tackle oil spills?

Publication date: 27/05/2010

Marine bacteria could be the key to cleaning oil spills in the sea, without
further damaging the environment by using chemicals, according to
microbiologists at Bangor University.

In the future, we could be harnessing naturally occurring microbes and
fertilizing them to increase their capacity to digest oil. These microbes are
found in seawater all over the planet. They naturally occur on microscopic
algae. Their numbers are regulated by the amount of their food source and
certain nutrients that they need to thrive.

The microbiologists at Bangor University are the first to trial this theory
in a systematic experiment, using seawater collected from the North Sea, the
Irish Sea and the Mediterranean. Their early results are strikingly similar-
suggesting that the system could be effective in a wide range of locations.

"The oil spill is an alternative digestible 'food source' for these microbes.
Although probably present in the Gulf of Mexico, for example, a shortage of
other essential nutrients limits their growth in numbers," explains Christoph
Gertler, of the School of Biological Sciences.

"What we have trialled is adding the nutrients these organisms need in the
form of a fertilizer, in a containing boom, for example. This enables the
microbes to multiply and, in the process, to break down and digest the
pollutant," he adds.

"Initially, we used the heaviest and most complex oil to biodegrade in small
scale experiments of 500 mililitres and managed to remove 95% of it simply by
applying these bacteria. In a second step, we scaled up the experiment to 500
litres and managed to remove virtually everything with the help of both bacteria
and an oil absorbing material. The next step would be to test the method in the
field on an actual oil spill as soon as possible."

"The potential for 'bioremediation' as this technique is called is huge. It
is, I believe, the only technique that would effectively remove oil that is
distributed over such large distances as are being seen in the current Gulf of
Mexico oil spill."

"Generally speaking, only collecting ("skimming") the oil from the water
surface, in-situ burning or biodegradation removes the oil from the ecosystem.
Dispersants only distribute it nicely."

Professor Golyshin explains: "The microbe used in the experiments --
Alcanivorax borkumensis - is extremely well adapted to oil degradation. It lives
solely on oil and dies after consuming all oil in its surrounding. Although it
is effectively able to survive and function in a range of temperatures above 5°
C, there are bacteria which perform this job in the Polar Zones, too. Bangor
University also investigates Oleispira antarctica which degrades oil in seawater
at freezing point."

He added, "Experiments in the lab have shown that -- given good growth
conditions - the bacteria initiate oil degradation very quickly within a week
after the oil spill and finish it within two months."

There's quite a lot of news around on this if you look for it - the Scientific
American, an NSF
grant, and the BBC,
for example. But much of this relates to the longer term whereas the Bangor
research demonstrates that it can be done now, with, it would seem, little likelihood of
unintended consequences. SO WHERE'S THE POLITICAL URGENCY, WHERE'S THE JUMPING UP AND DOWN ABOUT THIS?

[Image of Alcanivorax borkumensis at the head of this post from a Helmholtz
Centre article
in 1996; a good microbiological summary of Alcanivorax borkumensis can be found
here]

I just read in USA Today about urgent suggestions to use microbe friendly nutrients to expedite the oil decomposition. I hope that this is attempted very soon. A huge almost international effort has to be taken to mitigate this massive ecological/social disaster.

Good question, and, as usual, there isn't a simple answer. Natural crude oil contain thousands of different chemicals, and bacteria such as Alcanivorax are not interested in most of them. What they are interested in are the alkane compounds, molecules of carbon and hydrogen that provide the bacteria with energy and a source of carbon. They use the oxygen in seawater and their own specialized enzymes to break down the oil and process the alkanes, in the process emitting carbon dioxide. This still leaves a lot of the oil but, importantly, it's broken down and emulsified by the natural surfactants (glucose lipids) that the bacteria generate which, in turn, allows more rapid degradation. I'm not sure, but this emulsified oil may then be attacked by other bacteria whose favourite items on the menu are different from those of Alcanivorax.

That's about the limit of a geologist's understanding of microbiology! If anyone has further light to shed on this it would be much appreciated.

Another good question! The components of the oil form food for the bacteria, and, as long as it's available, they'll keep on dividing and multiplying. My understanding is that this will go on as long as food supplies last. Sorry I can't be more specific, not being a microbiologist!

As a microbiologist, I just wanted to throw in my two cents about the questions above. Michael is correct. A couple of things can happen to the oil being consumed by the bacteria. As you know, crude oil is a soup of different hydrocarbons and other chemicals. Different microbes prefer different components of the crude oil to preform different cellular tasks. Alcanivorax, for example, uses n-alkanes (or saturated hydrocarbons) primarily as a food source. Other microbes can use the hydrocarbons as the finial electron acceptor in cellular respiration. These microbes primarily use the aromatics and cyclical hydrocarbons in the crude oil. There are many species of oil degrading microbes which all use different parts of the crude oil so, in the end, the majority of the crude can be degraded naturally in the environment (like Michael, not agreeing with Rush or anything like that). After the oil is gone, the bacterial bloom will die, with the environment not being able to support the inflated biomass of the bacteria.

The one thing I believe I disagree with Michael about is that we should be adding these microbes to the gulf (correct me if I'm wrong, it seemed like you were suggesting this). There are already these bacteria there and it is very difficult to force bacteria into a niche that is already filled. In the past, adding microbes to the environment has failed (ex. Exon-Valdez spill tried this). What shows significantly more promise though is the addition of fertilizers to the spill site as nitrogen and phosphorous tend to be the limiting nutrients that slow the work down of the natural bacteria. Like with anything in the scientific community though, there is lively and ongoing debate about the subject and I can only present my opinion on the subject.

Ah - someone who knows what they're talking about - thanks for this, Matt! I became intrigued by this issue and, knowing virtually nothing about it, did a little digging around for facts as opposed to rhetoric. I soon discovered the (hardly surprising) complexities and the unknowns surrounding, for example, the idea of adding bacteria. It seemed to me that, firstly, the situation in the Gulf differed from the Exxon Valdez (lighter oil and warmer waters), and secondly that research had moved on. I certainly would not support wholesale ignorant messing around with the environment (unlike the sand berms construction...sorry, just had to say that) but a pilot project of bacterial "seeding" in a restricted area under controlled conditions might have been worth thinking about. After all, in terms of the temporary expansion of the food supply, that niche was suddenly less than full - but then I appreciate that bacteria are naturally quite good at responding to this anyway.

Debate, as long as it's considered and rational, is a good thing here - like everywhere!

If bacteria such as these hydrocarbon digesting bacteria could be manipulated to only uptake the spilt oil and not digest it, then do you believe if these bacteria were separated from their surroundings then this oil could be extracted,possibly for future use, and hence to prevent waste?

Luke - starting, as usual, with the disclaimer that I'm not a microbiologist, this is an interesting question, particularly since these bacteria thrive on any oil, naturally "spilt" or otherwise. However, since their metabolism is designed for breaking down oil components and extracting nutrients and energy, I'm not sure whether manipulating them not to digest the oil wouldn't be removing their whole reason for living! But then again, natural crude oil contains so many different constituents, and the bacteria focus only on a few, could useful ones remain in their systems? I honestly don't know.

However, there are rapid strides being made in amnipulating other bacteria to ingest organic waste and process it into useable hydrocarbons plus a variety of other chemicals - see

Some bacteria are very benefitial to our ocean. Things like pollution, including oils, that are consumed by wildlife cause diseases and change DNA in many of the ocean animals. If this oil is consumed by bacteria and goes up the food chain, wouldn't it somehow get into the bodies of fish consumed by humans or other wildlife? Woulnd't that create a catastrophic disaster? And how could all the bacteria possibly be removed from the ocean if it were found to cause massive problems?

Hi Julia. There are two key factors here - bacteria like alcanivorax consume components of oil to convert them into energy - they are the microbes' food, and therefore the original oil does not make it into the food chain. Also, the reason these microbes exist at all is that naturally occurring crude oil is widespread in the oceans, and hence they have evolved to feed on it.

It's easy to forget how beneficial bacteria are - to ourselves and the planet. The disaster would be in trying to remove them!